package com.adou.d9.api;

import java.util.StringJoiner;

public class Test4 {
    public static void main(String[] args) {
//        StringJoiner sj = new StringJoiner(",");
        StringJoiner sj = new StringJoiner(",", "[","]");
        for (int i = 0; i < 4; i++) {
            sj.add(""+i);
        }
        System.out.println(sj.toString());//0,1,2,3
    }
}
